There have been numerous efforts to market a product for dispensing a volatile fluid from a container through an applicator that is attached to the container. These attempts have failed or produced only marginally satisfactory products. None of these products could perform all of the important functions of controlling the flow of the stored fluid, preventing inadvertent or accidental flow of stored fluid, permitting the flow of vapors or gasses from the fluid in the container to the applicator tip while simultaneously preventing the flow of stored fluid through the applicator, and preventing drying out of the applicator tip after use or during periods of nonuse.
In the use of highly volatile fluids such as nail enamels, volatile paints, and correction fluid, the volatile fluid product is generally sealed in an air tight container. For application of such fluids directly from the sealed container, some pen type devices are marketed that permit the passage of these fluids through an applicator tip and include a check valve which is connected to the applicator tip. The check valve is opened by applying sufficient pressure to the tip and, when the pressure is released from the tip, the check valve closes. The valve thus acts as a shut off valve, the purpose of which is to prevent air from getting into the container and thereby preventing the product from drying out. Additionally, the shut off valve prevents the unintended release of the contained product by inadvertent squeezing or activation of the tube that contains the stored fluid. This shut-off valve design requires, however, that the applicator tip be made of a relatively hard substance such as metal. This arrangement is used, for example, in Pentel and Gillette correction fluid pens.
Another version of this type of shut-off valve design is used in the application of paints from a Tester's paint pen, and in the application of nail enamel from nail enamel pens marketed by Aziza and Margaret Astor. These devices use a fibre tip or porous plastic applicator.
A significant problem with these designs of shut-off valve type prior art devices is that the tip becomes damaged from repeated use as a result of the pressure that is required to open the shut-off valve, damage which adversely affects the functioning and use of the device.
Another problem is that once the product is used and a cap is placed on the applicator, any remaining fluid on the applicator quickly dries out and hardens, also adversely affecting subsequent use of the applicator.
The use of a soft or bristled application brush as the applicator tip is not possible with these constructions of shut-off valve type devices because the soft brush cannot withstand the pressure that is required to open the check valve. Yet products such as nail polish and the like cannot be effectively or satisfactorily applied to a work surface without a bristled brush or a similar soft and flexible applicator.
Attempts to overcome the rapid drying-out of the applicator tip have focussed on the use of a solvent cap, which requires that a solvent be placed or stored in the cap to saturate the applicator tip and thereby prevent its drying out when the cap is in place over the applicator. This introduces another problem because each time the cap is removed, solvent escapes from the cap so that the user must periodically replenish the supply of solvent. A prior art brush-on nail enamel pen product marketed by Beecham Cosmetics and developed by Schwan Stabillo used this approach and failed in the marketplace.